Innervation of the heart

Andrew Murphy and Dr Henry Knipe et al.

The heart has extrinsic and intrinsic innervation, which allows the heart to continue beating if the nerve supply to the heart is disrupted (e.g. in cardiac transplant).

The heart receives innervation from both the superficial and deep cardiac plexuses, which have both parasympathetic (from vagus nerve) and sympathetic inputs, which provide post-ganglionic fibers to the sinoatrial (SA) and atrioventricular (AV) nodes, as well other parts of the cardiac conduction system. 

The cardiac conduction system is composed of:

  • sinoatrial (SA) node
  • internodal connections
  • atrioventricular (AV) node
  • bundle of His
  • right and left bundle branches
  • Purkinje fibers

Cardiac myocyte conduction spreads through the heart from myocyte-to-myocyte starting the SA (pacing) node then via the other parts of the cardiac conduction in turn as outlined above. 

Each part of the cardiac conduction system has its own intrinsic pacemaker, which means that if a higher pacing center (e.g. SA node) is damaged and stops functioning a lower pacing center (e.g AV node) can take over. 

Anatomy: Thoracic
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Article information

rID: 26402
System: Cardiac
Section: Anatomy
Synonyms or Alternate Spellings:
  • Cardiac conduction system

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